About This Species
Unlike migratory species, Arctic shrews live in the Arctic year-round. They're solitary animals, who live about a year and a half in the wild. They eat bugs—like grasshoppers and sawflies—and help regulate pest populations in the ecosystem.
The pint-sized mammals are known for carrying both external and internal parasites, which make them a key link in the Arctic ecosystem. It also gives researchers insight into changes happening on the tundra. Because natural history museums have preserved specimen of the shrews from decades ago, scientists can recreate their diets and the parasite communities and compare them with modern shrews. The findings show that as the Arctic has warmed at an unprecedented rate, the shrews' ranges are shifting, with serious consequences.
Arctic shrews are classified by the International Union for the Conservation of Nature as a species of least concern, meaning there are a lot of them. During the Pleistocene era, they lived further south, as the region they currently inhabit was covered with ice.
The Arctic Shrews' Shifting Range
A study recently published in NOAA's 2016 Arctic Report Card examined two species of Arctic shrews. It found that as the climate continues to warm, the masked shrews of the forests will see their range expand northward, while the barren ground shrews of the tundra will see their range shrink and fragment.
The study found that in the past, the barren ground shrews lived throughout the northernmost parts of the Arctic during extended periods of cold. But with warmer temperatures, that is changing.
With the expansion of the masked shrew's range and with increased overlap between the two species, the study's authors project there could be an increase in disease as both species are introduced to new parasites.
Though many studies in the Arctic focus on megafauna, like polar bears or caribou, the shrews are significant not for their size but as a link in the Arctic ecosystem. They represent the near-bottom of the food chain and can be an indicator of larger environmental change.